1. Найдите значение выражения: 1) (−5/12 + 5/16) : (−13/72); 2) 9/14 − (−5/21) : (−2 9/14); 3) (7/16 − 31/40) : (−17/24 + 27/40); 4) −3 3/4 − (−8 2/9 − (−4,5) : 9/14) · 2 1/4.

1) \(\left(-\frac{5}{12}+\frac{5}{16}\right):\left(-\frac{13}{72}\right)=\left(-\frac{20}{48}+\frac{15}{48}\right)\cdot\left(-\frac{72}{13}\right)=\left(-\frac{5}{48}\right)\cdot\left(-\frac{72}{13}\right)=\frac{15}{26}.\)

2) \(\frac{9}{14}-\left(-\frac{5}{21}\right):\left(-2\frac{9}{14}\right)=\frac{9}{14}-\frac{5}{21}:\left(-\frac{37}{14}\right)=\frac{9}{14}+\frac{10}{111}=\frac{1379}{1554}.\)

3) \(\left(\frac{7}{16}-\frac{31}{40}\right):\left(-\frac{17}{24}+\frac{27}{40}\right)=\left(-\frac{47}{80}\right):\left(-\frac{13}{60}\right)=\frac{141}{52}.\)

4) \(-3\frac{3}{4}-\left(-8\frac{2}{9}-(-4.5):\frac{9}{14}\right)\cdot2\frac{1}{4}= -\frac{15}{4}-\left(-\frac{74}{9}+7\right)\cdot\frac{9}{4}= -\frac{15}{4}+\frac{11}{9}\cdot\frac{9}{4}= -\frac{15}{4}+\frac{11}{4}=-1.\)

Ответ: 1) \(\frac{15}{26}\); 2) \(\frac{1379}{1554}\); 3) \(\frac{141}{52}\); 4) \(-1\).